Thermal control material

A method for providing a thermal control material having high emissivity within a wavelength range of interest, comprising:

• fabricating one of a photonic crystal, a metamaterial, a metasurface, and a multilayer film on a first surface of a substrate;
• applying a layer of solid-state phase change material to the first surface of the substrate;
• and
• positioning a layer of reflective material at one of a second surface of the substrate, a surface of the solid-state phase change material, and an opposite side of an optical cavity from the substrate.

A thermal control material, comprising:

• a substrate patterned on a first surface to form an array of microcones;
• a layer of solid-state phase change material applied to the array of microcones;
• and
• a layer of reflective material applied to a second surface of the substrate.